Resistance of Arctic phytoplankton to ocean acidification and enhanced irradiance.

The Arctic Ocean is a region particularly prone to ongoing ocean acidification (OA) and climate-driven changes. The influence of these changes on Arctic phytoplankton assemblages, however, remains poorly understood. In order to understand how OA and enhanced irradiances (e.g., resulting from sea-ice retreat) will alter the species composition, primary production, and eco-physiology of Arctic phytoplankton, we conducted an incubation experiment with an assemblage from Baffin Bay (71°N, 68°W) under different carbonate chemistry and irradiance regimes. Seawater was collected from just below the deep Chl a maximum, and the resident phytoplankton were exposed to 380 and 1000 µatm pCO2 at both 15 and 35% incident irradiance. On-deck incubations, in which temperatures were 6 °C above in situ conditions, were monitored for phytoplankton growth, biomass stoichiometry, net primary production, photo-physiology, and taxonomic composition. During the 8-day experiment, taxonomic diversity decreased and the diatom Chaetoceros socialis became increasingly dominant irrespective of light or CO2 levels. We found no statistically significant effects from either higher CO2 or light on physiological properties of phytoplankton during the experiment. We did, however, observe an initial 2-day stress response in all treatments, and slight photo-physiological responses to higher CO2 and light during the first five days of the incubation. Our results thus indicate high resistance of Arctic phytoplankton to OA and enhanced irradiance levels, challenging the commonly predicted stimulatory effects of enhanced CO2 and light availability for primary production.

Inhibition of phorbol myristate acetate and phytohemagglutinin stimulation of human lymphocytes by retinol.

Retinol (vitamin A) in concentrations above (5 microgram/ml inhibits the stimulation of human lymphocytes by phytohemagglutinin and phorbol myristate acetate. This is in contrast to bovine lymphocytes in which retinol inhibits only phorbol myristate acetate stimulation of lymphocytes. The cause of the inhibition does not appear to be due to a direct toxic action because the viability and ultrastructure of lymphocytes exposed to a concentration of 20 microgram/ml for 72 hr were normal. The mechanism of action of the retinol is not known, but it may be mediated by a retinol-binding protein in the cells.

A comparison of faces scales for the measurement of pediatric pain: children's and parents' ratings.

Faces scales have become the most popular approach to eliciting children's self-reports of pain, although different formats are available. The present study examined: (a) the potential for bias in children's self-reported ratings of clinical pain when using scales with smiling rather than neutral 'no pain' faces; (b) levels of agreement between child and parent reports of pain using different faces scales; and (c) preferences for scales by children and parents. Participants were 75 children between the ages of 5 and 12 years undergoing venepuncture, and their parents. Following venepuncture, children and parents independently rated the child's pain using five different randomly presented faces scales and indicated which of the scales they preferred and why. Children's ratings across scales were very highly correlated; however, they rated significantly more pain when using scales with a smiling rather than a neutral 'no pain' face. Girls reported significantly greater levels of pain than boys, regardless of scale type. There were no age differences in children's pain reports. Parents' ratings across scales were also highly correlated; however, parents also had higher pain ratings using scales with smiling 'no pain' faces. The level of agreement between child and parent reports of pain was low and did not vary as a function of the scale type used; parents overestimated their children's pain using all five scales. Children and parents preferred scales that they perceived to be happy and cartoon-like. The results of this study indicate that subtle variations in the format of faces scales do influence children's and parents' ratings of pain in clinical settings.

The action of anti-A,AB isoantibodies on group A, AB-positive human lymphocytes.

Human lymphocytes of group A and group AB individuals were exposed to anti-A,B antisera both in growth medium and in fresh autologous plasma. Agglutination developed slowly but was present in all positive specimens by four hours and was negative in the group O controls even after 24 hours. There was no loss of viability even in the presence of the fresh plasma. The lymphocytes in the agglutinates appeared larger and more irregular suggesting stimulation of the lymphocytes but assessment by 3H thymidine uptake showed no evidence of a mitogenic response.